This invention relates generally to cardio stimulants or cardiotonic agents. More particularly, the present invention pertains to a novel cardiac composition containing a specific 5-phenylthiazole derivative as active ingredient.
We have previously reported on pharmacological analytical research concerning 4-phenylthiazole type compounds (J. Pharm. Dyn. 3, 85-93, 1980). As a result of further progress of the research, it has been found that 5-phenylthiazoles have novel pharmacological properties. More specifically, according to our discovery, as contrasted to 4-phenylthiazoles which generally inhibit the force of systolic contraction of specimens of the atrial muscle depending on the dosages administered, 5-phenylthiazoles markedly increase the force of systolic contraction of specimens of the atrial muscle according to the dosages administered.